The present invention relates to a scale removal system and a method for removing scale from apparatus, such as for example heat exchanges or condensers. In particular, the present invention relates to a scale removal system comprising a reverse osmosis generated water permeate feedstream and a pressurised carbon dioxide feedstream which combine to form a pressurised carbonic acid feedstream, and a method of using the scale removal system to remove scale deposits from apparatus.
Apparatus, such as for example heat exchangers and condensers, is prone to the build up of scale residue. As scale deposits form on the apparatus the effective cooling capability of the apparatus reduces due to the insulating properties of the scale residue. As a result, the amount of energy used by the apparatus increases. The scale residue must be regularly removed in order for the apparatus to continue to be used efficiently. Conventionally, solutions of strong mineral acids, such as for example sulphuric acid (H2SO4), are used to remove scale from the apparatus. There are however a number of disadvantages associated with the use of strong mineral acids. The use of strong mineral acids require extreme caution and can potentially corrode the apparatus if the process is not controlled carefully. As a result, the strong mineral acid may further reduce the useful life of the apparatus. The wastewater arising from the descaling process is also a hazardous waste. The wastewater must therefore be neutralised prior to disposal. Furthermore, the wastewater must be handled by a certified carrier and there are therefore significant additional costs associated with the disposal of the wastewater.
During the scale removal process, the apparatus is usually required to be removed from the process line. There are therefore a number of time constraints associated with disassembling the apparatus from the process line and reinstalling the descaled apparatus to the process line.
There is therefore a need for a system and a method for removing scale from apparatus which overcomes one or more of the above problems. In particular, there is a need for a system and a method for removing scale which does not require the use of highly corrosive material. There is also a need for a system and a method for removing scale which does not produce hazardous waste products, such as for example hazardous waste water. There is also a reed for a system and a method for removing scale which does not require water to be neutralised. There is also a need for a system and a method for removing scale which can be used in situ without requiring a process line to be disassembled for scale removal. There is also a need for a system and a method for removing scale which can be used quickly and efficiently.